A system-on-chip digital pH meter for use in a wireless diagnostic capsule

This paper describes the design and implementation of a system-on-chip digital pH meter, for use in a wireless capsule application. The system is organized around an 8-bit microcontroller, designed to be functionally identical to the Motorola 6805. The analog subsystem contains a floating-electrode ISFET, which is fully compatible with a commercial CMOS process. On-chip programmable voltage references and multiplexors permit flexibility with the minimum of external connections. The chip is designed in a modular fashion to facilitate verification and component re-use. The single-chip pH meter can be directly connected to a personal computer, and gives a response of 37 bits/pH, within an operating range of 7 pH units

Design of a single-chip pH sensor using a conventional 0.6-μm CMOS process

A pH sensor fabricated on a single chip by an unmodified, commercial 0.6-/spl μm CMOS process is presented. The sensor comprises a circuit for making differential measurements between an ion-sensitive field-effect transistor (ISFET) and a reference FET (REFET). The ISFET has a floating-gate structure and uses the silicon nitride passivation layer as a pH-sensitive insulator. As fabricated, it has a large threshold voltage that is postulated to be caused by a trapped charge on the floating gate. Ultraviolet radiation and bulk-substrate biasing is used to permanently modify the threshold voltage so that the ISFET can be used in a battery-operated circuit. A novel post-processing method using a single layer of photoresist is used to define the sensing areas and to provide robust encapsulation for the chip. The complete circuit, operating from a single 3-V supply, provides an output voltage proportional to pH and can be powered down when not required

Tranching in the Syndicated Loan Market

We use data comprising over 100,000 loans from 115 countries during 1995-2009 to examine factors that affect the extent of loan tranching, and the range of tranche spreads. The data show five factors that drive them: asymmetric information, borrower risk, transaction costs, the presence of institutional investors, and the legal system. Tranching is more extensive and generates greater differences in spreads between tranches of a same loan when asymmetric information and risk are more pronounced. Economic and institutional factors driving tranching are more directly applicable to non-investment grade loans. For developing countries, the data highlight factors that affect the extent of tranching but such factors show little sensitivity to the pricing of the relative spreads.Loan;Debt finance;Tranche;Law and finance

Radiative Hydrodynamic Simulations of HD209458b: Temporal Variability

We present a new approach for simulating the atmospheric dynamics of the close-in giant planet HD209458b that allows for the decoupling of radiative and thermal energies, direct stellar heating of the interior, and the solution of the full 3D Navier Stokes equations. Simulations reveal two distinct temperature inversions (increasing temperature with decreasing pressure) at the sub-stellar point due to the combined effects of opacity and dynamical flow structure and exhibit instabilities leading to changing velocities and temperatures on the nightside for a range of viscosities. Imposed on the quasi-static background, temperature variations of up to 15% are seen near the terminators and the location of the coldest spot is seen to vary by more than 20 degrees, occasionally appearing west of the anti-solar point. Our new approach introduces four major improvements to our previous methods including simultaneously solving both the thermal energy and radiative equations in both the optical and infrared, incorporating updated opacities, including a more accurate treatment of stellar energy deposition that incorporates the opacity relevant for higher energy stellar photons, and the addition of explicit turbulent viscosity.Comment: Accepted for publication in Ap

Run-up of Acquirer's Stock in Public and Private Acquisitions

Manuscript Type: Empirical Research Question/Issue: This paper empirically examines whether there is pre-announcement movement of an acquirer's share price and trading volume prior to the announcement of acquisitions in ways consistent with insider trading. Prior papers focus on insider trading of a target's stock; our paper differs by examining for the first time run-up of acquirer's stock, and considers both public and private acquisitions, including private-equity backed acquisitions. Research Findings/Insights: Acquisition announcements generate predictable movements in the price of the acquirer's stock. Pre-announcement trading in acquirer's stock is more likely to be attributable to insider trading when the pre-announcement price changes match the expected post-announcement acquirer returns. Based on a sample of Canadian acquirers and public and private acquisition targets from Canada, the US and 31 other countries over the years 1991-2008, we find evidence consistent with insider trading of acquirer's stock. Theoretical/Academic Implications: The evidence consistent with insider trading in this paper is limited to specific situations and is far from generalizable to all types of acquisition announcements. Post-announcement returns are typically negative for high Tobin's q acquirers, stock transactions, and foreign targets, but positive for private equity-backed private targets. We find economically and statistically significant evidence that pre-announcement run-ups move in ways that match these expected post-announcement effects. Pre-announcement movement in acquirer's stock largely depends on the type of acquisition announcement. Practitioner/Policy Implications: Our findings have significant policy implications for the allocation of surveillance efforts for initiating insider trading investigations. © 2011 Blackwell Publishing Ltd.preprin

Thermonuclear burst physics with RXTE

Recently we have made measurements of thermonuclear burst energetics and recurrence times which are unprecedented in their precision, largely thanks to the sensitivity of the Rossi X-ray Timing Explorer. In the "Clocked Burster", GS 1826-24, hydrogen burns during the burst via the rapid-proton (rp) process, which has received particular attention in recent years through theoretical and modelling studies. The burst energies and the measured variation of alpha (the ratio of persistent to burst flux) with accretion rate strongly suggests solar metallicity in the neutron star atmosphere, although this is not consistent with the corresponding variation of the recurrence time. Possible explanations include extra heating between the bursts, or a change in the fraction of the neutron star over which accretion takes place. I also present results from 4U 1746-37, which exhibits regular burst trains which are interrupted by "out of phase" bursts.Comment: 4 pages, 2 figures, AIP conference proceedings format. To appear in the proceedings of the "X-ray Timing 2003: Rossi and Beyond" meeting held in Cambridge, MA, November, 200

The European Union in Sudan: a missed opportunity?

International organisations active in Africa are often criticised for their ineffectiveness. So too is the European Union (EU), which is also accused of failing to assume a more prominent conflict management role in war-torn countries. This article examines the EU’s capacity and readiness to take on such a role in one such country, the former Republic of Sudan, home to Africa’s longest-running civil wars and the first ‘genocide’ of the 21st century. It begins by outlining the EU’s record in Darfur and the North–South Peace Process. Drawing upon 25 interviews and Hill’s ‘capabilities–expectations model’, it then questions whether the EU’s ‘capabilities’ (resources, instruments, unity) were ‘fit for purpose’ in Sudan’s hostile target setting. It concludes by identifying settings that have been more propitious for a conflict-related management function and by suggesting that the EU should better manage expectations about future security roles

Fabrication of submicron planar Gunn diode

We present, for the first time, the fabrication process for a submicron planar Gunn diode in In<sub>0.53</sub>Ga<sub>0.47</sub>As on an InP substrate operating at 265 GHz. A novel two stage lift off method has been developed to achieve a submicron gaps between contacts down to 135 nm with widths up to 120 μm